Half of the people living with HIV are over the age of 50 – and over the next decade, researchers expect that number to jump to as many as three-quarters of the 1.2 million Americans affected by the virus.
With age comes the diseases of aging, like cancer. In fact, cancer is now the leading cause of death among people with HIV, and prostate cancer is among the most diagnosed cancers for this group, said epidemiologist Ashish Deshmukh, Ph.D., co-leader of the Cancer Control Research Program at MUSC Hollings Cancer Center.
Yet it's not clear how HIV may affect the typical progression of prostate cancer that doctors are familiar with or how it might affect standard treatments.
Deshmukh has teamed up with long-time collaborators Keith Sigel, M.D., Ph.D., professor in the Division of Infectious Diseases at Icahn School of Medicine at Mount Sinai, and Elizabeth Chiao, M.D., a professor in the Department of Epidemiology, Division of Cancer Prevention and Population Sciences at The University of Texas MD Anderson Cancer Center, to model the effects of HIV and HIV treatment on prostate cancer.
The trio received a $3.4 million grant from the National Cancer Institute that will provide guidance on optimal ways to manage prostate cancer among people with HIV.
"There is significant uncertainty regarding how prostate cancer should be managed in persons with HIV," Deshmukh said. "HIV-associated immunosuppression may interfere with disease progression, so persons with localized prostate cancer may have a higher risk of progressing more rapidly to intermediate risk, for example. We don't know differences in quality-of-life and whether HIV-associated comorbidities may affect outcomes."
"There is significant uncertainty regarding how prostate cancer should be managed in persons with HIV. HIV-associated immunosuppression may interfere with disease progression, so persons with localized prostate cancer may have a higher risk of progressing more rapidly to intermediate risk, for example."Ashish Deshmukh, Ph.D.
Sigel noted that few studies have looked at this specific population of cancer patients.
"This grant is significant because very little research has been done on the impact of HIV on prostate cancer's progression and treatment," Sigel said. "Prostate cancer is an important and understudied cancer for people with HIV. Researchers at Mount Sinai are using a variety of cutting-edge tools to improve our understanding of these two diseases and help manage this cancer better in this population."
For example, a typical patient diagnosed with low-risk prostate cancer may be advised to start active surveillance. Low-risk prostate cancer is slow-growing, and treating it could result in more side effects and worse quality of life than leaving it alone. Under active surveillance, the patient gets more frequent and intensive check-ins to monitor whether the cancer is growing.The patient and his doctor can then decide when it's time to start actively treating the cancer.
This typical pattern may not work for people with HIV, though. Their immunosuppressed status, as well as antiretroviral therapy medications taken daily, likely affect how quickly and aggressively the cancer grows as well as the likelihood of serious side effects from cancer treatment, the researchers suspect.
"Recent advances in surgery, radiation therapy, and chemotherapy have greatly enhanced prostate cancer care. Yet, a data gap exists regarding its management and outcomes in HIV-positive men. We are excited to build on our collaborative research efforts to provide evidence-based best practice guidance for men living with HIV and prostate cancer," Chiao said.
To understand how HIV affects prostate cancer, researchers will create an HIV/prostate cancer simulation model that will generate a data-driven virtual "in-silico" – that is, one performed on a computer or via computer simulation – trial by integrating information from several real-world databases into an existing HIV natural history simulation model that they've conceptualized and developed.
"We use simulation modeling for questions that are not answerable in the real world," Deshmukh explained.
It wouldn't be ethical, for example, to test the effectiveness of cancer screening by refusing to screen one group and then comparing them to a group that did get screened.
In this case, the simulation model will allow them to create a simulated clinical trial to provide evidence-based and personalized guidance and concurrently inform treatment recommendations.
The researchers hope that their work will not only provide treatment guidelines to improve survival for people with HIV who are diagnosed with prostate cancer, but also protect their quality of life.
